The industrial applicability of urea-formaldehyde polymers has been known from some time. These polymers find use in diverse applications from use in the agricultural industry to use as an additive in paper, paint, and varnish applications. In the paper industry, it is known that urea-formaldehyde polymers can be used to improve opacity and printability. However, in agricultural applications, the urea-formaldehyde polymers serve mainly as a carrier for an active ingredient. Typically, the active ingredient is deposited into the cavities and onto the surface of the urea-formaldehyde polymer by dissolving the active ingredient in a solvent, and spraying this solution onto the surface of the urea-formaldehyde polymer in a fluidized bed drier. The solvent is volatized by the hot air in the fluidized bed dryer, producing a urea-formaldehyde polymer coated with the active ingredient.
However, the inventors hereof have discovered that some solvents presently used do not completely volatize, and the incomplete volatilization of the solvent limits the amount of active ingredient deposited onto the urea-formaldehyde polymer carrier. In addition, fluidized bed driers are specialized pieces of equipment requiring extensive and expensive air handling and conditioning capabilities. Therefore, there is a need in the art for a process whereby urea-formaldehyde polymer can be effectively coated with active ingredients.